The damage from destroying your Presence is part of the same action because the Special Rule says "When you destroy your Presence..." – it modifies how other actions work while they're happening. Tags: Destroy, Saved From Destruction, Action Modifiers, Damage, 25 more...
Similarly, if a Power allows adding multiple token types in combinations you choose (e.g., Utter a Curse of Dread and Bone), Intensify can only add extras of token types that are already being added. And if you could add tokens in multiple places (e.g., Spill Bitterness into the Earth), you can only add extra tokens where you already added tokens of that type. Tags: Spirit tokens, Action Modifiers, Hazards Spread Across the Island, Utter a Curse of Dread and Bone, 5 more...
A land is always at exactly Range 0 of itself, and therefore "within Range 1," "within Range 2," etc.
If a land meets a particular condition (e.g., "with Dahan"), it's its own "nearest land" meeting that condition.
Isolating a land doesn't change any of these answers, since none require checking which other lands are adjacent.
For some practical examples:
It's impossible to Push a piece from a land to itself or Gather a piece from a land to itself, since those move to/from adjacent lands.
The threshold of "The Land Thrashes in Furious Pain" (Major Power) can't Repeat that Power on the original target land, since that land is not adjacent to itself.
The first threshold of "Explosive Eruption" (Volcano Looming High's left Innate Power) can deal damage in the target land (the land where the Power destroyed Presence). Also, the third and fourth thresholds of both deal damage in the target land.
During the Dahan Insurrection Scenario, if a City is destroyed in a land with Dahan, then "Military Response" adds a Town in that same land because there is no nearer land with Dahan.
"Exports Fuel Inward Growth" (The Kingdom of Scotland Level 6) adds Towns to a land with Towns/Cities even if there are no adjacent Towns/Cities (either "naturally" or due to Isolate). Tags: Isolate, Push, Gather, Range, 27 more...
Use the Power as though the number in the "Range" box were increased or completely ignored (depending on the Range boost in question) and the extra target requirement were included in the "Target Land" box. In the case of Shadows of the Dahan, this means ignoring the Range number entirely (but not anything else in the "Range" box!) and adding "Dahan" to whatever else is already in the "Target Land" box.